Secure your wordpress site (https) fast and free with Virtualmin and Let’s Encrypt

Google wants everything on the web to be travelling over a secure channel. That’s why in the future your Chrome browser will flag unencrypted websites as insecure, displaying a red “x” over a padlock in the URL bar.With this upcoming change in Chrome, Google makes it clear that the web of the future should all be encrypted, and all sites should be served over HTTPS, which is essentially a secure layer on top of the usual HTTP web protocol. In this post we are going to see how to secure your wordpress site (https) easily, fast and free by using Virtualmin  web hostign control panel and Let’s encrypt free, aytomated and open certificate authority (CA). This procedure works for Joomla sites too.



Virtualmin is a web hosting control panel, designed to make it easy to manage websites, mailbox users, databases, and web applications. It provides website owner accounts, easily installable web applications, file management, and a comprehensive and easy to use API for integration with billing and support systems. Installing Virtualmin provides a full-featured web hosting stack with web, email, databases, spam and antivirus filtering, analytics, and much more. Virtualmin is the easiest and fastest way to turn a Linux system into a full-featured web hosting system, and it is fully integrated with Webmin.

Let’s Encrypt

Let’s Encrypt is a free, automated, and open certificate authority (CA), run for the public’s benefit. It is a service provided by the Internet Security Research Group (ISRG).

They give people the digital certificates they need in order to enable HTTPS (SSL/TLS) for websites, for free, in the most user-friendly way we can. We do this because we want to create a more secure and privacy-respecting Web.


Step 1:

Login into webmin backend and in the virtualmin menu click on Edit Virtual Server –> Enabled features –>SSL website enabled

Step 2:

Go to Server configuration menu –> manage ssl certificate –> Lets encrypt –> Request certificate

Step 3:

Login into wordpress backend –> Settings –> Genenal –> Change the URLs of WordPress Address and Site Address to https://yourdomain.comStep 4 :

Download Velvet Blues Update URLs plugin to make yor links and references to point to your new domain name.

Step 5:
Check your homepage. If it has the Secure green lock you’ve done it. There is a possibility that your site will not be fully secured unless you change some links you’ve manually entered into the theme settings. So the best way to resolve this is to inpect your webpage to see which mixed resources your site use and fix it.



Wanhao 3d 2.1 Print ok hand

Wanhao Duplicator i3 v2.1

I recently ordered a Wanhao Duplicator i3 Plus 3D printer from through  for 379£ + 25£ shipment =406£. 1 week later I had the package in my hands. After opening it I realised they had sent me a Wanhao Duplicator i3 v2.1!!. I emailed them and they told me that it was a mistake and they were willing to collect and resend me the original one or to refund me with 100£. I couldn’t wait for another week and more so I chose the second option and I kept the Wanhao Duplicator i3 v2.1. The 2 printers print with almost the same quality, the only differences are with the interface. The plus is more friendly to the final user (touch screen) with some minor improvements to the cable management.

Wanhao Duplicator i3 v2.1 Characteristics:

  • Included Printing Material: 10 Ft. of Black PLA Filament (Standard) or 2 PLA Filament Rolls (Optional)
  • Extruder: MK10 Single-Extruder
  • Filament Size: 1.75mm Dedicated
  • Top Hotend Temperature: 260°C (Short-term), 240°C (Long-term)
  • Layer Capability: 0.1mm (100 microns)
  • Build Envelope: 200mm x 200mm x 180mm (8in. x 8in. x 7in.)
  • Build Surface: Heated Bed Plate and Wanhao Adhesive Sheet
  • Filament Capabilities: PLA, ABS, PVA, Stainless Steel, NinjaFlex, Nylon, HIPS, Woodfill, LayBrick, CopperFILL, BronzeFILL, MOLDLAY, Conductive, Carbon Fiber, Polyurethane plus more!
  • Compatible Software: Repetier (Opensource), CURA (Opensource), MatterControl (Opensource), Simplify 3D (Details)
  • File Type: Gcode
  • File Transfer: microSD Card & USB
  • Frame Color: Steel Frame (Powder Coated Black)
  • Warranty: 1 Year FREE parts replacements and FREE in-shop service


The assembly was easy and the first prints were better than I expected. 

The wanhao duplicator i3 V2.1 is a pretty decent 3D printer. For the price is a perfect way to get into the world of 3D printing with very good results. It has some cons like the cable management, some noisy bearings etc but nothing that it can’t be fixed easily with the help of the large and resourceful community of the Wanhao duplicator i3 owners which is at the same time the greatest plus of the printer. 

How to flash a ZTW Spider 30A OPTO ESC with the latest SimonK firmware by using an AFRO USB programmer

Parts needed:

ZTW Spider 30A OPTO Esc

Afro ESc USb Programming Tool

RapidFlash ESC Chrome App


  1. Connect ESC to the AFRO ESC Usb programming tool (the – and the signal pin)
  2. Connect the battery to the ESC
  3. Open RapidFlash app
  4. Choose the COM where Afro USB tool is connected to
  5. Choose Afro ESC USB linker
  6. Choose Latest (master)
  7. Choose bs_nfet as your firmware
  8. Press Flash Firmware (click in the reverse box if you want the motor the run into the opposite direction)

How to mount Tarot TL65B44 rectactable landing gear onto the Tarot 650 frame

I have recently bought 2 Tarot TL65B44 electric landing gears for my Tarot 650 from Banggood for 32 euros (link). But unfortunately there were not any instructions into the package. So after some research I think the best way to mount those landing gears is by unscrewing the plate of the landing gear and turning it 180 degrees so that the motor heads to the opposite direction. Then by using 3 screws as you can see into the photos below you can mount the landing gears below the lower plate of the tarot 650 frame.

TL65B44 Small Electric Retractable Landing Gear

TL65B44 Small Electric Retractable Landing Gear

UAS Photogrammetric Point Clouds: A Substitute for LiDAR?

Download the pdf here

No topic in the remote sensing community was hotter in 2014 than Unmanned Aerial Systems (UAS) and it appears that will also hold true for 2015. Arguably the biggest UAS news over the past few months has been the commercial release of LiDAR systems for UAS, with a number of manufacturers succeeding in reducing the size of their LiDAR sensors so that they can be mounted on UAS platforms. Given that there is now LiDAR-based UAS it begs the question as to why one would even consider a photogrammetric UAS solution in which topographic data are produced from overlapping images?

Despite the advances made in shrinking LiDAR sensors, they are still larger and heavier than the cameras used for photogrammetric UAS solutions. LiDAR sensors thus require a larger UAS platform with greater lift capacity than a comparable photogrammetric UAS. Larger UAS platforms have an inherently greater risk associated with them. There is a big difference between a 1.5 lb. Styrofoam fixed-wing UAS loosing power and gliding to the ground versus a 17 lb. hexicopter with a LiDAR sensor falling from the sky.

LiDAR UAS solutions are also substantially more expensive and require a higher level of technical expertise to operate. With a lower purchase price, smaller and safer platform, and ease of operation, photogrammetric UAS options are an attractive solution to those seeking on-demand topographic mapping. This begs another question, are UAS photogrammetric solutions accurate enough? I will get to that answer later, but first a bit of a back story.

Commercial photogrammetric UAS have been around for a number of years. I first became interested in these systems a number of years ago when Hurricane Irene devastated Vermont’s transportation network by dumping inches of rain in a matter of hours, flooding roads, and leaving one town completely cut off from the outside world. Despite the vast network of satellite and aerial systems capable of delivering remotely sensed data, cloud cover and challenges in compiling a collection deck in a timely manner confounded acquisition.

Even if these issues had been resolved it was not clear that the data could have been delivered with requisite specifications within a timely manner. Fixing roads required mapping-grade, or in some cases, survey-grade data to make detailed measurements. Traditional field survey techniques were not possible in many cases due to the inherent dangers involved, and the extent of damage would have exhausted the number of surveyors available even if it were possible. In the absence of data, decisions, such as estimating fill volume for washed-out roads, were often made using the tried, but certainly not true, “ocular estimation” approach.

UAS certainly seemed to be the remote sensing solution needed for these types of situations. With funding from the U.S. Department of Transportation we set out to evaluate the ability of commercial UAS photogrammetric solutions to deliver GIS-ready data suitable for accurate measurements and mapping. We purchased a senseFly eBee, a lightweight (1.5 lb.) UAS with a 38 inch wingspan that uses a digital camera to produce orthoimages and photogrammetric point clouds in LAS format.

Generating these products requires accurate flight planning, to insure sufficient image overlap, and photogrammetric post-processing software. The eBee is accomplishes this through a tightly integrated workflow in which eMotion software is used to plan the flights (Figure 1) and Pix4D’s Postflight software is used to produce the 2-D and 3-D products (Figure 2). While any system requires some level of expertise it is hard to imagine making it any easier to generate photogrammetic point clouds than the eBee does.

Before I get into the accuracy of products from photogrammetric UAS it is important to discuss their capabilities and limitations. The eBee, and similar systems, are small, lightweight, and battery powered. Onboard systems track the location using GPS and gather key flight parameters such as wind speed. The FAA’s proposed small UAS 500 foot flight ceiling means that such a system could map several hundred acres in a 30-40 minute flight. By using a few batteries you can map a good-sized area, but you are not going to map your town (at least in a day) with one of these small UAS.

Now let’s get to the fun stuff–point clouds! Figure 3 shows a point cloud produced using the eBee workflow. As mentioned before the point cloud is in LAS format, which opens up traditional workflows developed for LiDAR data. Quick Terrain Modeler, Applied Imagery’s popular terrain analysis software was used to display the point cloud and perform the cross section profiles of the stream.

The point cloud looks stunning, but there are some obvious differences when compared to LiDAR. There are some data voids caused by shadows and there are no points under the tree canopy. The points are not data rich like LiDAR (e.g. no return information), but they are colorized automatically from the imagery, and unlike LiDAR, there are points for the water.

There are some obvious errors, but given that Figure 3 shows only 1/6th of a dataset gathered in a 30-minute flight, followed by 2 hours of post-processing with little user intervention, the results are impressive. Getting a point cloud for a couple of miles of river the same day you fly it would have been unheard of a few years ago.

How do photogrammetic point clouds stack up to LiDAR? Figures 4a and 4b show a UAS photogrammetric point cloud and a traditional LiDAR point cloud from a manned fixed wing collect processed to USGS QL2 specs for the same area. If you are having second thoughts that the point clouds are of the same area you are not the blame. The traffic circle seen in the UAS point cloud was constructed after the LiDAR was acquired.

This gets to one of the chief advantages of UAS, the ability to gather high-resolution topographic data when you need it, at a low cost. The UAS point cloud obviously has a higher point density, averaging nearly 50 points per square meter, compared to the nearly 3 points per square meter of the LiDAR data. Point density is, of course, not a definitive measure of quality. Despite that ground control points (GCPs) were not used, the UAS data were within half a meter of the LiDAR data on the horizontal plane, but the absolute vertical difference exceeded 50 meters.

GCPs narrowed the differences to tens of centimeters, both horizontally and vertically. GCPs do add another layer of complexity to the UAS data collection, and in disaster response, laying out GCPs might not be feasible due to time or safety constraints. For a number of use cases relative vertical measurements are what is needed.

With this in mind we measured a number of buildings that remained consistent in the two datasets (Figures 5a and 5b). Differences in the height measurements were always less than 30 centimeters, indicating that rapid accurate relative vertical measurements are possible using photogrammetric UAS workflows.

The title of this article was slightly provocative, and one could be tempted to slide into the LiDAR vs photogrammetry debate. Photogrammetric point clouds are certainly not LiDAR point clouds, but when factors such as cost, safety, timeliness, and acquisition area are considered, they might offer a superior solution. I believe that photogrammetric UAS will offer attractive solutions to many mapping and survey projects for years to come. Recent advances in photogrammetric UAS, such as the eBee RTK, which yields data with horizontal and vertical accuracies of less than 5 centimeters, will blur the lines between LiDAR and photogrammetic point clouds.

Disclaimer: The views, opinions, findings and conclusions reflected in this presentation are the responsibility of the authors only and do not represent the official policy or position of the USDOT/OST-R, or any State or other entity.

Jarlath O’Neil-Dunne is the Director of the University of Vermont Spatial Analysis Laboratory. He specializes in solutions that provide actionable information from high-resolution remotely sensed data.

Download the pdf here